Understanding Light and Vision: Properties and Phenomena
Light: Electromagnetic Waves
Light is a form of energy that propagates through space without the need for a material medium. It consists of electric and magnetic fields that are perpendicular to each other and to the direction of propagation.
Key Features of Light
- It does not need a material medium for propagation.
- Electric (E) and magnetic (B) fields vary sinusoidally with position (x) and time (t).
- It is caused by accelerating electric charges, which lose energy that propagates as electromagnetic waves.
Mastering Photography: Techniques and Film Development
Depth of Field
Depth of field refers to the area in front of and behind the subject that appears sharp in a photograph. In other words, it is the zone of acceptable sharpness within a photo that will appear in focus. Several factors influence the depth of field:
- Aperture: The aperture controls the amount of light reaching the film or sensor.
- A more open aperture (smaller f-number) results in less depth of field.
- A more closed aperture (larger f-number) results in more depth of field.
- Focal Length:
- A longer
Thermal Engineering Principles: Condensation, Boiling, and Radiation
Film and Dropwise Condensation
- Film Condensation:
- A continuous liquid film forms on the surface as vapor condenses.
- The film acts as a thermal resistance, reducing heat transfer efficiency.
- Common in practical systems due to impurities and surface characteristics.
- The heat transfer rate is generally lower compared to dropwise condensation.
- Dropwise Condensation:
- Condensed vapor forms droplets instead of a film on the surface.
- Offers higher heat transfer rates due to minimal thermal resistance.
- Droplets grow,
Wave Properties, Electric Charge, and Induction
Wave Classifications
There are several possible classifications of waves.
By Medium of Propagation
Electromagnetic and gravitational waves do not need a material medium to propagate and can, therefore, propagate in a vacuum. Examples of electromagnetic waves are: light, radio waves, television and mobile phones, microwaves, ultraviolet rays, gamma rays, etc.
Mechanical waves need a material medium to propagate. Examples include: sound, water waves, and vibrations of a string. These waves are the result
Read MoreAngular Momentum, Kepler’s Laws, and Universal Gravitation
Angular Momentum of a Particle
The angular momentum of a particle about a point O is the vector product of its position vector with respect to that point and its momentum:
The angular momentum is measured in SI units of kg * m2/s. It is a vector quantity, perpendicular to r and v. Its magnitude is “sen” where is the angle between r and v. Whenever r and v are parallel, the angular momentum is 0. The angular momentum characterizes the rotational motion of the particle.
Variation of Angular Momentum
This
Read MoreForce and Motion Problems: Solutions and Calculations
Force and Motion: Solved Problems
Strength: solutions
Problem 1
A body with a mass of 600 kg accelerates at 1.2 m/s². What force caused this acceleration?
Data:
- m = 600 kg
- a = 1.2 m/s²
Solution:
F = ma = 600 kg * 1.2 m/s² = 720 N
Problem 2
What mass must a body have for a force of 588 N to accelerate it at 9.8 m/s²?
Data:
- F = 588 N
- a = 9.8 m/s²
Solution:
m = F / a = 588 N / 9.8 m/s² = 60 kg
Problem 3
A 250 kg body is subjected to two opposing forces: 5880 N to the right and 5000 N to the left. What is the